Late Evening Notes and the 10 pm Advisory: Debby a Little Stronger

Here are my notes late this evening.

RECON DATA
AF Recon found a central pressure of 1001 mb and maximum flight level winds of 47 mph. Maximum observed surface winds were 38 mph, so Debby remains weak and disorganized.

Three low-level penetration missions are tasked for Sunday. The Gulfstream IV is not scheduled at this time.

MOIST ENVIRONMENT
The storm is in a very moist environment with no dry air anywhere near. Microwave satellite imagery does not indicate a core is close to forming, which suggests rapid intensification is not imminent.

RAPID INTENSIFICATION POTENTIAL
The SHIPS model, however, puts a decent probability on rapid intensification in the next 36 hours before landfall.

OFFICIAL TRACK
The official track has Debby making landfall around 11:30 AM Monday between the Aucilla and Econfina Rivers, west of Perry, Florida, in fairly uninhabited Taylor County.

MODEL MADNESS
– HWRF Model: Predicts landfall near St. Marks around 7 AM CDT Monday with a pressure of 982-983 mb.
– HMON Model: Indicates an earlier and weaker landfall, occurring Sunday evening, and is considered an outlier.
– HAFS-A Model: Predicts landfall at 10 AM Monday near or east of St. Marks with a pressure of 988 mb.
– HAFS-B Model: Predicts landfall at 7 AM Monday near St. Marks with a pressure of 988 mb.
– GFS Model: Predicts landfall near St. Marks Monday morning around 7 AM with a pressure of 987 mb.
– Euro Model: Weaker and further east, predicting landfall around Keaton Beach with a pressure of 999 mb.
– Model Uncertainty: It is too early to read much into the models at this point as they have not locked onto good data yet.

IMPACTS ON ALABAMA
Debbie will bring wind gusts to 25 mph to the southeastern quarter of Alabama late Sunday into Monday and a few showers and storms to that part of the state. We should not see tornadoes, but we will be carefully watching any outer feeder bands.

IMPACTS ALONG THE BEACHES
Those gusty northerly winds and a high rip current risk especially for eastern beaches including the beaches of 30A eastward through Panama City and St. Joe and St. George.

QUICK FACTS
———————————————–
LOCATION…24.4N 83.6W
ABOUT 50 MI…80 KM WSW OF THE DRY TORTUGAS
ABOUT 260 MI…415 KM SSW OF TAMPA FLORIDA
MAXIMUM SUSTAINED WINDS…45 MPH…75 KM/H
PRESENT MOVEMENT…NW OR 320 DEGREES AT 14 MPH…22 KM/H
MINIMUM CENTRAL PRESSURE…1003 MB…29.62 INCHES

No change in warnings:

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for…
* Florida coast from Aripeka northward to Indian Pass

A Storm Surge Watch is in effect for…
* Florida coast from Bonita Beach northward to Aripeka, including
Tampa Bay and Charlotte Harbor

A Hurricane Warning is in effect for…
* Florida coast from the Suwannee River to the Ochlockonee River

A Hurricane Watch is in effect for…
* Florida coast west of the Ochlockonee River to Indian Pass
* Florida coast south of the Suwannee River to Yankeetown

A Tropical Storm Warning is in effect for…
* The Florida Keys west of the Seven Mile Bridge including the Dry
Tortugas
* Florida coast south of the Suwannee River to East Cape Sable
* Florida coast west of the Ochlockonee River to Indian Pass

A Tropical Storm Watch is in effect for…
* The Florida Keys north of the Seven Mile Bridge to the Channel 5
Bridge
* Florida coast west of Indian Pass to Mexico Beach

SUMMARY OF NHC DISCUSSION
Here are the key talking points from the 10 pm NHC discussion on Tropical Storm Debby:

1. Intensity and Structure:
– Debby’s winds have increased slightly, with maximum sustained winds now at 40 knots (46 mph), and the central pressure has fallen to 1003 mb. The storm is gradually intensifying in a low shear environment with warm waters, particularly as it approaches the Florida Big Bend area.

2. Track and Movement:
– Debby is moving northwest at 12 knots but is expected to slow down and turn northward, reaching the Florida Big Bend region within the next day or two. After landfall, the storm’s motion will slow further, with the potential to creep northeastward across northern Florida and near the Georgia and South Carolina coasts by day 5. There is uncertainty about the exact location of the storm on day 5, but it is expected to move slowly, which could lead to significant rainfall and flooding.

3. Strength and Forecast:
– Models indicate that Debby could strengthen to a hurricane before landfall, with the potential for rapid intensification. The NHC forecast has been increased to 75 knots (86 mph) within 36 hours. The storm’s intensity after landfall remains uncertain, depending on whether it moves back over the Atlantic.

4. Key Hazards:
– Heavy rainfall is expected to cause considerable flash and urban flooding across Florida and the Southeast coast through Thursday, with significant river flooding likely.
– Hurricane conditions are expected along the Florida Big Bend region on Monday, with tropical storm conditions beginning late Sunday. The Tampa Bay area and the Lower Florida Keys may also experience tropical storm conditions.
– There is a risk of life-threatening storm surge from Aripeka to Indian Pass, and potentially southward to Bonita Beach, including Tampa Bay and Charlotte Harbor.
– The storm’s impacts, including storm surge, strong winds, and heavy rains, could extend into Georgia and the Carolinas. Additional watches and warnings may be issued as the system progresses.

Category: Alabama's Weather, ALL POSTS, Tropical